Crank-shaft bearing of bicycles.



No. 697,944. Patented Apr. l5, I902] F. JOHNSON.

CRANK SHAFT BEARING UF BICYCLES.

(Application filed Jam 24. 1900.)

2 Shams-Sheet I.

(No Model.)

No. 697,944. Patented Apr. l5, I902.

F. l. JOHNSON.

CRANK SHAFT BEARING OF BICYGLES.

(Applitation filed Jan. 24. 1900.)

(No Model.) 2 s heets sheet 2.

rm: Nnnms PETERS co. PHDTO-LIYHQ, WASHINGTON, u c.

ATE

i'rn FREDERIO I. JOHNSON, OF FITOHBURG, MASSACHUSETTS.

CRANK-SHAFT BEARING OF BICY'CLES.

SPECIFICATION forming part of Letters latent No. 697,944, dated April15, 1902.

Application filed January 24,1900- Serial No. 2,607. (N0 model.)

To all whom it may concern.-

Be it known that I, FREDERIC I. JOHNSON, a citizen of the United States,residing at Fitchburg, in the county of \Vorcest'er and Commonwealth ofMassachusetts, have invented a new and useful Improvement in theCrank-Shaft Bearings of Bicycles, of which the following is aspecification, accompanied by drawings forming a part of the same, inwhich- Figure 1 represents that part of a bicycleframeknownasthecrankhangerorbracket. Fig. 2 represents the same view as shown inFig. 1, except that the sleeve which suports the crank-shaft isrepresented as having been turned or rotated in the crank-bracket. Fig.3 is a front View of my improved crankhanger. Fig. l is a detached viewof the sleeve in which the bearings of the crank are placed, providedwith eccentric rings fitting the barrel forming the crank-bracket. Figs.5, 6-, and 7 represent the eccentric rings detached from the sleeve, andFig. 8 is a detached View of the sleeve with the position of the ringsthereon represented by broken lines.

Similar reference-figures refer to similar parts in the different views.

My invention relates to that class of crank hangers or brackets in whichthe crank-shaft rotates within bearings held in a sleeve which iseccentrically journaled Within the crankbracket; and my inventionconsists in an im proved method of constructing theeccentrically-journaled sleeve containing the crankshaft. Sleevescontaining a crank shaft which is eccentrically journaled in the crankhanger or bracket of a bicycle have been heretofore made for the purposeof varying the position of the crank-shaft in order to tighten or loosenthe bicycle-chain, and their use willbe well understood. Sucheccentrically-journaled crank sleeves or bearings have been usually madefrom a single piece of drop-forged steel and the surplus stock removedby milling; but this method of construction is very expensive, and mypresent invention consists in an improved method of construction bywhich the cost and weight are reduced.

Referring to the accompanying drawings, 1 represents the transverse tubeknown as the crank hanger or bracket and forming a part of the frameworkof the bicycle, portions of which are shown at 2, 3, and 4. Within thecrank hanger or bracket 1 is held a sleeve 5, having brazed on each enda thin eccentric ring 6, and brazed to its central portion is a thickeccentric ring 7. The rings 6 6 are circular plates cut from sheetmetal, fitting the crank-hanger tube 1, and are provided with eccentricholes 8, tightly fitting the periphery of the sleeve 5. The eccentricring 7 is of similar construction, except that it is thicker, in orderto give a greater bearingsurface upon the sleeve 5 and furnishsufficient stock to receive the radially-projecting screw-threaded pinor stud 9, which is screwed into the ring 7 and projects through theslot 10, formed in the crank-hanger 1, and carries a clamping-nut 11,which is screwed against the outside of the crank-hanger 1 in order tohold the crank-sleeve 5 in its desired position in the crank-hanger. Byloosening the nut 11 and moving the stud the length of the slot- 10 thesleeve 5 is rocked in the crank-hanger from the position shown in Fig. 1to that shown in Fig. 2, thereby varying the axis of the sleeve 5 andchanging the position of the crank, so that the sprocket-chain of thebicycle may be tightened or loosened, as desired. The rings 6 and 7 areupon the outside of the sleeve 5 and securely brazed thereto, forming anextremely light and cheaply-constructed eccentric bearin The increasedthickness of the central eccentric ring 7 affords a suflicientattachment to the sleeve 5, and as the rings 6 are only required tosupport the ends of the sleeve and are not subject to severe strain theyare cut from lighter sheet metal. All the eccentric rings are cheaplymade by stamping or punching from sheet metal and are readily brazed inposition, allowing the sleeve to be finished before the rings areattached.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. In a bicycle, the combination with the barrel of the crank-bracketprovided with a slot, of a sleeve adapted to receive the crankshaft, apair of eccentric rings attached to the ends of said sleeve, a thickeccentric ring attached to the central section of said sleeve, saideccentric rings fitting the barrel of the crank-bracket, a studprojecting radially from IOU said central ring through the slot in saidbarrel and a clamping-nut carried by said stud by which the sleeve isheldfrom rotation in said barrel, substantially as described.

2. In a bicycle, the combination with the barrel of the crank-bracketprovided with a slot, of a sleeve adapted to receive the crankshaftconsisting of a piece of tubing and having brazed 0r soldered eccentricrings fitting said barrel, with a screw-threaded stud proj ectingradially from one of said rings through said slot and a clamping-nutcarried by said studgsubstantially as described.

In testimony whereof I have signed my name to this specification, inpresence of two I 5 subscribing witnesses, this the 22d day of January,1900.

FREDERIO I. JOHNSON.

Witnesses:

J. WM. JOHNSON, B. STODDARD.

